* Albert Einstein: The book incorporates the concept of "tesseract," a concept from Einstein's theory of relativity, which allows for travel through time and space.
* Plato: The concept of the "Central Intelligence" in the book mirrors Plato's idea of the "Form of the Good" in his allegory of the cave. The "Central Intelligence" represents a universal truth and wisdom.
* Ancient Greek Mythology: The "Happy Medium," a character in the book, is a reference to the ancient Greek concept of a spirit that guides and connects the living and the dead.
It's important to note that these references are not literal portrayals of historical figures but rather inspirations and allusions that add depth and complexity to the story.